Carburetor



June 24, 1930. w. c. CARTER CARBURETOR Filed May 17, 1926 Patented June 24, 1930 PATENT OFFICE WILLIAM C. CARTER, OIF FLINT, MICHIGAN CARBURETOR Application led May 17, 1926'. Serial No. 109,660.

This invention relates to carburetors of the type, in which the throttle valve is used to govern the admission of air to the mixing chamber, and is arranged adjacent the air inlet end of said mixing chamber.

One object of my present invention is to provide a carburetor which is of such design that a very low vacuum in the intake manifold of the engine; say, for example, a vacuum about one-third of that ordinarily used, is sufficient to draw the proper amount of fuel into the intake when the engine is operating under a heavy load with a wide open throttle. Another object of my present invention is to provide a carburetor that is equipped with a novel means for maintaining the flow of the fuel in proper proportion to the flow of the air in all positions of the throttle valve. Other objects and desirable features of my invention will be hereinafter pointed out.

The carburetor herein illustrated, which represents the preferred form of my invention, is equipped with a suction amplifier arranged so that when the engine is idling, with the throttle valve closed, said amplifier will be inactive, and when the throttle valve is moved into its open position, said amplifier will become active automatically to exert additional suction on the fuel supplying means of the carburetor. The throttle valve is provided with a center opening that constitutes a passageway through which atomized fuel is admitted to the mixing chamber when the engine is idling, with the throttle valve closed,

center passageway in the throttle valve and to prevent the high vacuum which exists in the mixing chamber when the throttle valve is closed from being exerted on one portion of the liquid fuel supplying means. When the throttle valve is moved into its open position the center passageway of the throttle valve is enlarged and the suction in the mixing chamber is exerted on the fuel supplying means in such a way as to automatically increase the supply of fuel to the mixing chamber. The liquid fuel supplying means consists preferably of a plurality of fuel ducts leading from a liquid fuel reservoir and arranged so that one of said ducts is operative,

r and a valve is usedvto vary the size of the' at all times for supplying liquid fuel to an atomizing chamber and the other duct is rendered operative by opening the throttle valve. A displacement member is preferably combined with the throttle valve so as to operate in unison with same and raise the level of the fuel in the liquid fuel reservoir when the throttle valve is moved into its open position. I wish it to be understood that various changes can be made in the construction and arrangement of the suction amplifier without departing from the spirit of my invention, that the carburetor can be equipped with any suitable kind of liquid fuel supplying means; and that the displacement member and the parts which co-operate with the same to maintain the ow of fuel in proper proportion to the flow of the air in all positions of the throttle valve, are not limited to use in a carburetor equipped with a suction amplifier.

Figure l of the drawings is a vertical sectional view of a carburetor constructed in accordance with my present invention, showing the throttle valve closed. mi

Figure 2 is a similar view, showing the throttle valve open.

Figure 3 is a horizontal sectional View, taken on the line 3 3 of Figure 1, looking in the direction indicated by the arrows; and

Figure 4 is a vertical sectional view, taken on the line 4-4 of Figure 1, looking in the direction indicated by the arrows.

Referring to the drawings which illustrate the preferred form of my invention, A designates the air intake chamber of the carburetor, A. designates a choke valve for said chamber, and B designates a tubular member arranged in said air intake chamber in longitudinal alignment with the intake pipe of the engine on which the carburetor is used, so as to form the mixing chamber C of the carburetor. The tubular member B is preferably contracted intermediate its ends so as to form a venturi and the throttle valve D is provided with al tapered peripheral edge and is arranged so that it will be positioned within the intake end of the venturi B when said valve isA in its closed position. In accordance with usual practice the throttle valve is adapted to be adv'usted so that it is crackeddischarge end of same will always be located within the venturi B even when the throttle valveis in its wide open position, as shown in Figure 2; The throttle valve D is reciprocatingly mounted and is carried by a displacement member F that slides vertically in a tubular portion 1 in the body portion of the carburetor arranged below and in concentric relation with the venturi B said sleeve 1 serving as a liquid fuel reservoir 2 to which liquid fuel is supplied from a float chamber G through a fixed orifice 3v or any other suitable form of fuel supplying device. Any suitable means can be used to open and close the throttle valve to cause the displacement member F to move downwardly into the body of fuel in the reservoir 2 when the throttle valve is opened thus raising the level of the fuel in said reservoir, and to move upwardly when the throttle valve is moved towards its closed position, thus lowering the level of the fuel in the reservoir 2. In the carburetor herein illustrated the means that is used for this purpose consists of a manually-operated pinion 4 that meshes with a rack 5 on the displacement member F. The pinion 4 is attached to a shaft 6 to which an operating lever 7 is connected as shown in Figure 4, and in order to prevent the fuel from leaking through the opening around the shaft 6, I arrange a gasket 8 of cork or some other suitable material between the pinion 4 and the member 9 through which the shaftI 6 projects and use a coiled expansion spring 10 to exert endwise pressure on the pinion 4 so as to cause it to press tightly against the gasket 8. Obviously any other suitable means can be used to pack the joint through which the shaft 6 extends, but I prefer to use a means of the kind described, as it overcomes the necessity of adjusting a device at frequent intervals so as to maintain a tight joint around the shaft 6.

A mixture passageway or atomizing chamber 11 is formed in the upper end portion of the displacement member F and a valve 12 is provided for controlling the center opening or passageway in the throttle valve through which atomized fuel escapes from said atomizing chamber 11 and passes upwardly through the venturi Eon the throttle valve D. Various means can be used for admitting air and liqu-id fuel to the mixture passageway or atomizing chamber 11. In the carburetor herein illustrated -the liquid fuel supplying means consists of a fuel duct 13 that establishes direct communication at all times between the liquid fuel reservoir 2 and an extension or depending portion of the mixture passageway 11 and a separate and distinct duct or plurality of ducts 14 that discharge liquid fuel from the reservoir 2 into the path of the current of air that enters the mixture passageway 11 when the throttle valve is in its open position. v The sleeve 1 on the body of the carburetor that Aconstitutes the fuel reservoir 2 is open at its upper end and terminates inside of the air intake chamber A. The displacement member F is constructed or proportioned with relation to the diameter of the reservoir 2 that downward movement of the member F into the body of liquid fuel in said reservoir causes said fuel tolbe transferred from the bottom to the top of the reservoir, not by pressure produced by the downward movement of the member F, but instead, by the displacement of the liquid in the reservoir when the member F moves downwardly through said liquid. When the throttle valve is set in its closed position, as shown in Figure 1, the upper ends of the fuel ducts 14 are positioned above the level of the fuel in the Hoat chamber of the carburetor, and when the throttle valve is moved into its open v position, as shown in Figure 2, the upper ends of said ducts 14 are positioned below the level of the fuel in the float chamber. The fuel duct 13 is herein illustrated as being formed in the outer surface of a rod 15 that projects upwardly through the displacement member F and which is attached at its upper end` to the valve 12, lpreviously referred to, that is used to vary the size of the center opening in the throttle valve D through which the atomized fuel is introduced into the mixing chamber. The fuel duct or ducts 14 are formed in the exterior of the displacement member F, and in most instances two, or more of said ducts will be arranged symmetrically in-the exterior of the displacement member F so as to tend to cause the liquid fuel to be distributed evenly into the current of air that enters the vaporizing chamber 11 when the throttle valve is open. The particular form of the displacement member F is immaterial, however, so long as said member is constructed in such a way that it is capable of moving freely in the reservoir 2 to eect the displacement of the fuel in said reservoir.

The throttle valve D is adapted to be set or adjusted so that when the engine .is idling, with the throttle valve closed, as shown in Figure 1, air will be .drawn around the edge of said throttle valve into the intake end of the venturi B, and atomized fuel will be drawn into the mixing chamber through the venturi E on the throttle valve. At such times liquid fuel stands in the downward extension or depending portion of the mixture passageway 11 and air is drawn into said passageway 11 in a path above the level of the fuel in the float chamber through air ports 16 in the upper end portion of the displacement member F, the iniowing air picking'up the fuel delivered to the depending portlon of the passageway 11 by the duct 13 and carrying said fuel upwardly past the valve 12 and through the venturi E into the mixing chamber C. Due to the fact that the upper ends of the'fuel ducts 14 are in direct communication with the air intake chamber A of the carburetor and the upper end of the fuel duct 13 terminates in the downward extension or depending portion of the mixture passageway 11 which is under a considerably higher suction than the main air intake chamber A when the throttle valve is closed, no fuel will be drawn out of the fuel ducts 14 by the 'air which enters the mixture passageway or vaporizing chamber 1l when the throttle valve is closed. When the throttle valve is moved into its open position, however, the fuel ducts 14 come into service and cause a relatively great quantity of liquid fuel to be atomized and drawn-into the mixing c hamber through the venturi E. In order, to attain this result the valve 12 is arranged in such relation with the throttle valve D that movement of said throttle valve towards its open position enlarges the center opening in the throttle valve controlled by the valve 12; air inlet ports 16 are formed in the upper end ofthe displacement member F to admit air to the atomizing chamber 11, and a tapered device 17 is arranged on the under side of the throttle valve so as to co-operate with the upper end of the sleeve 1 in which the displacement member slides. Movement of the throttle valve towards its open position shown in Figure 2 enlarges the passageway in said throttle valve controll-ed by the valve 12 and also causes the air flowing to the mixture passageway 11 to travel in a lower path, due to the downward movement of the air inlet ports 16. This movement of the throttle valve also causes the tapered device 17 on the under side of the throttle valve to move downwardly into the open upper end of the sleeve 1, thus diminishing the size of the passageway through which the air is traveling from the air intake chamber A into the vaporizing chamber 11. The result is that the suction on the upper ends of the fuel ducts 14 and on the fuel supplyorifice 3 is increased, and the path of travel of the airflowing to the vaporizing chamber 11 will be changed from a horizontal plane above the level of the fuel in the float chamber to a horizontal lane below the level of the fuel in the float c amber. In other words, the carburetor is so designed that when the throttle valve is in its closed position, as`

shown in Figure 1, the air that is drawn into the atomizing chamber or mixture passageway 11 through the ports 16 by the suction in the mixing chamber, will travel in a ath above the level at which the fuel stan s in the ducts 14, and after the throttle valve has moved into its open position, as shown in Figure 2, the member F in which the air inlet ports 16 of the atomizing chamber 11 are formed will have moved downwardly 'sufficiently to cause said ports 16 to be arranged at a point below the level of the fuel in the float chamber, due, of course, to the fact that the downward movement bf the member F displaces the fuel in the reservoir 2. Accordingly, the ar, 1n entering the atomizing chamber 11, will iow in such a path as to cause fuel to be drawn out of the ducts 14 and carried into the atomizing chamber 11.

In order that the supply of atomized fuel to the mixing chamber C through the center opening of the throttle valve l) may be regulated so as to supply the proper quantity of fuel at idle engine speeds, l use a tapered valve l2 for controlling the opening through.

which the atomized fuel passes from the atomizing chamber 11 into the venturi E, and provide a means for raising and lowering said valve so as to change the position of same relatively to the throttle valve, said.

valve adj ust-ing means being herein illustrated as consisting of a manually-operable screw 18 that bears against the lower end of the rod 15 which carries the valve 12. rl`he duct 13 through which the liquid fuel passes from the reservoir 2 into the mixture passageway 11 is so constructed that downward movement of the throttle valve towards its open position increases the effective area of said duct. This is accomplished by forming the duct 13 in the exterior of the rod 15 at a point above a reduced portion of said rod formed by a fiat surface 13a thereon, and mounting said rod 15 in the displacement member F in such a way that the portion of said rod in which the duct 13 is formed is positioned in a hole 13b in the displacement member when the throttle valve is in its closed position, as shown in Figure 1. When the throttle valve is moved downwardly into its open position, as shown in Figure 2, the displacement member F shifts relatively to the rod 15, thereby causing the reduced portion 13a' of said rod to become positioned in the hole 13b in the displacement member, and consequently, permitting more fuel to pass from the reservoir 2 into the mixture passageway 11 in the displacement member.

Any suitable means can be used for governing the admission of liquid fuel from the supply pipe 19 into the float chamber G, the means herein illustrated consisting of a tapered valve 20 arranged so that it seats in the same direction that the liquid fuel flows into the float chamber, a coiled expansion spring 21 'arranged underneath said valve and disposed so that it constantly exerts an upward pressure on said valve, and a lever 22 for unseating said valve, arranged with its free end in engagement with a guide rod 23 connected to the float 24 inthe float chamber. When the level of the liquid in the float chamber drops, the fioat 24 moves downwardly, thereby causing the lever 22 to open the valve 20 and permit the liquid fuel to enter the float chamber through the supply pipe 19, and thereafter, when the float moves upwardly, due to a rise in the level of the fuel in the fioat chamber, the spring 21 seats the valve 20.

-The suction amplifier that constitutes one feature of my present invention, consists of a device I that is arranged inside of the member E that forms the center opening of the throttle valve, so as to increase the suction on the fuel supplyin means when the throttle valve is open, there y making it possible to carry a very low vacuum in the intake manifold of the engine, say, for example, a vacuum of one-third that of common practice, and still obtain the proper supply of fuel to the engine when the engine is operating under a heavy load with a wide open throttle. The suction amplifier I preferably consists of a venturi arranged inside of the venturi E on the throttle valve, with its upper end portion or discharge portion projecting upwardly above the contracted portion of the venturi E, and spaced far enough away from the flared intake portion of said venturi E to form a passageway provided with air inlet ports 25. I/Vhen the engine is idling with the throttle valve closed, the suction amplifier I is inactive, and at such times the high vacuum that exists in the mixing chamber is exerted only on the fuel supply duct 13, thereby causing atomized fuel to be drawn upwardly past the valve 12, through the suction amplifier I, and thence through the venturi E into the mixing chamber. Vhen the throttle valve is moved into its open position, as shown in Figure 2, the air supply ports 25 in the flared, intake portion of the venturi E are brought into the air intake chamber A of the carburetor. Consequently, the air that flows upwardly through the annular space between the venturis B and E will exert a suctionon the discharge end of the venturi E, and thus cause air to enter the air inlets 25 in the flared. intake portion of the venturi E and flow upwardly through said venturi, thereby amplifying or increasing the suction that is exerted on the fuel supply ducts 13 and 14 bythe vacuum in the mixing chamber. When the throttle valve is restored to its closed position, the suction amplifier I is automatically rendered inactive. v

From the foregoing it will be seen that my improved carburetor is provided with a plurality of venturis arranged so that they will produce different effects at different stages of the throttle valve, the venturi I constituting a suction amplifier which increases the suction on the fuel supplying means to such an extent when the throttle valve is open, that it is possible to carry a very low vacuum in the intake manifold of the engine and still obtain the proper amount of fuel when the engine is operating under a heavy load with a wide open throttle. The carburetor is also equipped with a novel means of simple design or maintaining the flow of the fuel in proper proportion to the flow of the air in all positions of the throttle valve.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A carburetor provided with a mixing chamber, a throttle valve, a tubular member connected with said throttle valve and arranged to project into the mixing chamber, said tubular member serving as an opening through which atomized fuel is'introduced into the mixing chamber, a venturi inside of said tubular member mounted in fixed relation with the same and spaced away from the side wall of said tubular member so as to form an air passageway, and air inlet ports for said passageway located above the throttle valve.

2. A carburetor, comprising a mixing chamber, a throttle valve, a venturi attached to the throttle valve and arranged so as to constitute a passageway through which atomized fuel is introduced into the mixing chamber, a second venturi inside of the venturi on the throttle valve in fixed relation with the ysame and spaced away from the interior thereof so as to form an air passageway, and air inlet ports for said passageway located above the throttle valve.

3. A carburetor provided with a venturi through which air flows towards the intake of the engine, a throttle valve for controlling the flow of air through said venturi, a second venturi rigidly mounted on the throttle valve and arranged so as to constitute a passageway for atomized fuel, a third venturi arranged inside of the venturi on the throttle valve in fixed relation with the same and spaced away from the interior thereof so as to form an air passageway, and means whereby air will be caused to circulate through said passageway in a direction to exert a suction on said third venturi when\the throttle valve is in its open position.

4. A carburetor, comprising a mixing chamber, an air intake chamber, a throttle valve for governing the admission of air from said intake chamber to said mixing chamber, a liquid fuel reservoir whose upper end terminates inside of said air intake chamber and is in communication with same, means for supplying fuel to said reservoir, and a displacement member in said reservoir arranged to move in unison with the throttle valve and constructed so that movement of the throttle valve towards its open position causes said displacement member to move downwardly towards the bottom of said reservoir, and raise the lever of the fuel in said reservoir.

5. A carburetor, comprising a mixing chamber, an air intake chamber, a throttle valve provided with an opening through which atomized fuel is admitted to said mixing chamber, a liquid fuel reservoir whose upper end is open and in communication with said air intake chamber, a displacement member arran ed to operate in unison with the throttle vagve and adapted to move downwardly into said reservoir and displace the fuel therein when the throttle valve is moved into its open position, an atomizing chamber in said displacement member provided with an air inlet port, a fuel duct for establishing direct connection between said fuel reservoir and said atomizing chamber, and a valve that varies the size of the opening in the throttle valve through which the atomized fuel passes, when the position of said throttle valve is changed.

6. A carburetor provided with a mixing chamber, an air intake chamber, a throttle valve arranged adjacent the inlet end of said mixing chamber, an opening in said throttle valve through which atomized fuel is admtted to said mixing chamber, a liquid fuel reservoir whose upper end communicates with the interior of said air intake chamber, a displacement member in said reservoir arranged to operate in unison with the throttle valve, a mixture passageway in said displacement member, a fuel duct leading from said reservoir to said mixture passageway, a separate fuel duet leading from said reservoir to the air intake chamber, and a valve for the opening in the throttle valve arranged so as to prevent the high suction that exists in the mixing chamber when the throttle valve is closed from being exerted on said second fuel duct.

7'. A carburetor provided with a mixing chamber, an air intake chamber, a throttle valve for governing the admission of air to said mixing chamber provided with an opening through which atomized fuel is admitted to the mixing chamber, a liquid fuel reser. voir, a displacement member in said reservoir arranged to operate in unison with the .throttle valve, a vaporizing chamber in said displacement member provided with an air inlet means, separate fuel ducts leadinnr from said reservoir for supplying liquid fhel to the air that is drawn into said vaporzing chamber, and means whereby movement of the throttle valve towards its closed position causes the air being admited to the Vaporizing chamber to travel in a lower path relatively to the level of the fuel in the fioat chamber of the .carburetor and also increases the suction on themeans which supplies fuel to said incoming air.

WILLIAM C. CARTER. 

